docs: def update(self, **kwargs):
          """
          Updates all elements in the current QuerySet, setting all the given
          fields to the appropriate values.
          """
          query = self._build_query()
          connection = get_es_connection(self.es_url, self.es_kwargs)
          results = connection.search(query, indices=self.index, doc_types=self.type,
                                               model=self.model, scan=True)
          for item in results:
              item.update(kwargs)
              item.save(bulk=True)
          connection.flush_bulk(True)
          # Clear the result cache, in case this QuerySet gets reused.
          self._result_cache = None